Headbox for paper making machine



y 1967 F. J. GEDEMER HEADBOX FOR PAPER MAKING MACHINE Filed Dec. 14,1964 g am/wvkoh i MUM JQ/UQWU United States Patent 3,332,837 HEADBOX FORPAPER MAKING MACHINE Fred J. Gedemer, Appleton, Wis., assignor to Allis-Chalmers Manufacturing Company, Milwaukee, Wis. Filed Dec. 14, 1964,Ser. No. 418,154 7 Claims. (Cl. 162-347) This invention relates to papermaking machines and in particular a headbox providing control of Paperweb formation on such as a Fourdrinier wire in a manner that providesparticularly advantageous control for making light and tissue weightpaper.

In forming light weight paper on a Fourdrinier paper machine it isnecessary that the headbox deposit paper stock on the Fourdrinier wirewith a spouting velocity that is at nearly as possible equal to thespeed of the Wire. In order to achieve such stock velocity with a highspeed wire, the headbox maintains a pressure on the stock. To reduce apossibility to such a high velocity stream being deposited on the wirewith turbulence that could cause the stream to be of somewhat uneventhickness, the stream is discharged over a lower lip and beneath anupper lip that projects farther downstream than the lower lip, to coverthe initial web forming area. This initial web forming area beneath theprojecting upper lip may be at least partly over wire still on thefarthest upstream supporting roll, called the breast roll. With such anarrangement the breast roll may be of a type having peripheral openingfor receiving water passing through the wire before it leaves the breastroll. Internal suction boxes may also be provided within such a breastroll to collect such water within the roll and to drain away suchcollected water.

Such headboxes have often included rigid plate structures carefully andcritically designed to achieve a suitable smooth surface of accuratecurvature to conform to the desired drainage profile over the breastroll. Usually adjusting linkages are associated with the enclosure sothat the dimensions of the forming zone may be varied somewhat dependingon the type of stock being used. These adjusting linkages are usuallyfairly complex and massive because it is essential to provide highlyaccurate positioning of the headbox sections defining the drainageprofile so as to avoid undesirable interference with the smooth flow ofthe stock stream and even deposit of the fiber in the web forming area.

It is an object of the present invention to provide a new and improvedadjustable drainage defining profile for a headbox that will depositstock upon a rapidly moving wire and achieve precise control of webformation on a Fourdrinier wire.

It is another object of the present invention to provide a new andimproved adjustable drainage defining profile for a headbox, withadjusting linkages preloaded so there will be no relative movementbetween links as a result of slightly loose fits arising from practicallimitations on the degree of manufacturing tolerances that can beachieved.

It is also an object of the present invention to provide for an initialadjustment of the vertical spacing over the wire of the outer edge ofthe upper lip of the headbox outlet and an additional adjustment for thethroat of the headbox outlet without moving the initial position of thatedge of the upper lip.

According to a preferred embodiment of the present invention, a pressureheadbox is provided with a stock reservoir having a movable front wallassembly with a lower portion extending forward of the top of thereservoir to define a forwardly extending upper lip of a stock outletopening projecting over a portion of a forming wire on a breast roll.The forward edge of the upper lip may be located over the turning axisof the breast roll where the wire begins its horizontal reach off thebreast roll.

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A vertical support wall extends forward of the top portion of theheadbox reservoir and upwardly of the upper lip of the stock outlet. Apantographic linkage assembly is connected to the vertical support wallwith the links defining a plane parallel to the vertical plane of thesupport wall. The pantographic linkage assembly has three vertical linksand a pair of vertically spaced parallel links transverse to thevertical links. The links are pivotally connected together at eachintersection. The forward ends of the transverse links extend forward ofthe support wall where they are pivotally connected at vertically spacedlocations on the forwardmost vertical link. The rearward ends of thetransverse links are pivotally connected to vertically spaced locationson the rearmost vertical link and to the support wall near the rear ofthe support wall. The vertical link intermediate the forward and rearvertical links is pivotally connected to the transverse links and thesupport wall near the front vertical edge of the support wall. Theintermediate and rearward vertical links extend downwardly to a locationbelow the lower transverse link to locations spaced above the forwardlyprojecting upper lip of the stock outlet where these ends are pivotallyconnected to the support wall.

A first lifting device is connected to the top of the forwardmostvertical link, which is arranged over the forward edge of the upper lip.This lifting device is operative to pivot the forward end of the supportwall about the lowest pivotal connection on the rear link andaccordingly lift or lower the forward edge of the upper lip to providean initial adjustment of the clearance of the upper lip of the stockoutlet over the wire where the wire begins its horizontal reach off thebreast roll. A second lifting device is pivotally connected to the topof the rear link. After the first lifting means is operated to establisha desired clearance of the upper lip over the wire, the throat profileof the outlet to the rear of the forward edge of the upper lip can beadjusted without changing the established clearance of this edge overthe wire. This can be accomplished by operating the second liftingdevice to pivot the rear end of the support wall and the upper lip aboutthe forward edge of the upper lip which is established as the pivotalaxis for such movement with the described linkage. Certain arrangementsaccording to the prior art provide for lifting a rear portion of anupper lip of a stock outlet but without establishing a pivotal axiscoincident with the forward edge of the upper lip. Therefore, when suchprior art arrangements are operated in that manner, each adjustment ofthe throat profile changes the clearance over the wire. Operators havehad the experience with such prior art arrangements of unintentionallylowering the forward edge of the upper lip on the rapidly movingFourdrinier wire and chopping through the wire. Therefore, it is animportant advantage of the present invention that the Fourdrinier wirecannot be cut when adjusting the rear portion of the upper lip to changethe profile of the throat of the stock outlet.

To provide for very accurate adjustment of the front wall assembly ofthe headbox, all of the pivotal connections referred to are preloaded toeliminate uncontrolled movement as a result of small but unavoidableclearances in the pivotal connections. This is accomplished by a thirdlifting device pivotally connected to the support wall above the uppertransverse link and between the intermediate and rear vertical links.Sufficient lifting force is applied by this third lifting device toplace all connections in the described pantographic assembly under load.Operation of the assembly of the present invention therefore neverapplies a force to an unloaded connection and all parts are always intheir fully loaded positions within clearances ready to move underprecise control without any need to first move to take up slack in looseconnections.

Other objects and advantages of the present invention will appear fromthe following more detailed description with reference to theaccompanying drawing which shows a partly sectional vertical view of aheadbox according to the present invention.

The movable front wall assembly 17 is provided with upper portions 22and portions 23 extending forward of the portions 22 terminating 'with aforwardly extending upper lip 24 over stock outlet opening 19. The upperlip 24 projects over a portion of forming wire 10 on breast roll 11. Theforward edge 25 of the upper lip 24 may be located over the turning axisof the breast roll where the wire 10 begins its horizontal reach off thebreast roll 11.- A vertical support wall 30 extends forward of the topwall portion 22 and upwardly of the lower wall portions 23 and upper lip24 of the stock outlet 13. A pantographic linkage assembly 31 isconnected to the vertical support wall 30 with links defining a planeparallel to the vertical plane of the support wall 30. The pantographiclinkage assembly 31 has three vertical links 32, 33, 34 and a pair ofvertically spaced parallel links 35, 36 transverse to the vertical links3234. The links 32-36 are pivotally connected together at eachintersection by connecting shafts 37*42. The forward ends of thetransverse links 35, 36 extend forward of the support wall 36 where theyare pivotally connected by shafts '3'7, 38 to vertically spacedlocations on the forwardmost vertical link 32. The rearward ends of thetransverse links 35, 36 are pivotally connected by shafts 41, 42 tovertically spaced locations on the rearmost vertical link 34: Thevertical link 33 intermediate the forward and rear vertical links 32, 34is pivotally connected by shafts 39, 46 to the transverse links 35, 36.The intermediate link 33 and rearward vertical link '34 extenddownwardly below the lower transverse link 36 to locations where theseends are pivotally connected by shafts 43, 44 to the support wall 30 anddefine a plane XX coincident with edge 25 and parallel to links 35, 36.

A first lifting device 48 is pivotally connected by a shaft 49 to thetop of the forwardmost vertical link 32 which is arranged over theforward edge 25 of the upper lip 24 to establish the edge 25 as the axisabout which wall 30 pivots when adjusted by means that will hereinafterhe described. The device 48 includes a depending rod i) connected to apower shaft 51 by any suitable arrangement such as, for example, a rackand pinion assembly (not shown).

A second lifting device 54 is pivotally connected by a shaft 55 to thetop of the rear link 34. The device 54 includes a depending rod 56connected to a power shaft 57 which may also be by any suitablearrangement such as, for example, a rack and pinion assembly (notshown).

A third lifting device 60 for prel-oading all connecting shafts 37-44 ofthe pantographic linkage assembly 31, has a rod 61 pivotally connectedby a shaft 62 to the sup port wall 30. The upper end of rod 61 projectsthrough a floor plate 63 which is fastened to wall members 64 pivotallyconnected to a support bracket 65 by a shaft 66. A piston 67 is fastenedto the top of rod 61 above the floor plate 63. One or more annularexpansible air bags 68 may be arranged around the rod 61 and in thespace between the floor plate 63 and piston 67. The lifting devices 48,54, 60 are each mounted on brackets 70, 71, 72, respectively, which arein turn carried by support structure '73.

The top edge 74 of the upper wall portion 22 is beveled to slopeupwardly in the direction toward the support wall 30. This edge 74engages a pivotal bracket 75 and the edge 74 can slide on pivotalbracket 75 to maintain a closed connection with top wall 16 as the frontwall assembly 17 is moved during operation such as will now bedescribed. Joints between the front wall assembly 17, the side walls 14and bottom wall 15 maybe sealed in any conventional manner, for example,by flexible seals or packing (not shown).

In the operation of the described apparatus, air bag 68 is filled withair pressure to push upwardly upon piston 67 and lift rod 61 and supportwall 30 to preload the pivotal connections of the linkage assembly 31 atshafts 3744. The clearance of lip 24 and edge 25 over wire 10 isadjusted when power shaft 51 of the lift-ing device 48 raises rod 50 topivot the forward end of the support wall 36 about the lowest pivotalconnection at shaft 44 on the rear link 34. This movement may be appliedto provide an initial adjustment of the clearance of the upper lip 24 ofstock outlet 19 over the wire it where the wire begins its horizontalreach off breast roll 11.

After the first lifting device 48 is operated to establish a desiredclearance of the upper lip 24 over the wire it the throat profile of thestock outlet 19 to the rear of the forward edge 25 of the upper lip 24,can be adjusted without changing the established clearance of this edge24 over the wire 10. This can be accomplished by operating the secondlifting device 54 to raise or lower shaft 56 and link 34 to pivot therear end of the support wall 39 and the upper lip 24 about the forwardedge 25 of the upper lip 24 which is established as the pivotal axis forsuch movement with the described linkage 31. Because the pivotal axisfor such movement is the edge 25, an operator can devote full attentionto adjusting the profile of stock outlet 19 with-out concern aboutinadvertently chopping wire 10 with edge 25. Furthermore, because allconnections at the shafts 3744 are preloaded, precise control isachieved for accurate adjustment of the elevation of edge 25 over wireit and the profile of outlet 19 rearward of edge 25.

From the foregoing it will be understood that the present invention ispossessed of unique advantages. However, such modifications andequivalents of the disclosed concepts such as readily occur to thoseskilled in the art are intended to be included within the scope of thisinvention and thus the scope of this invention is intended to be limitedonly by the scope of the claims such as are, or may hereafter be,appended hereto.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. -In a paper machine having a looped forming wire, a stock flowdistributing headbox comprising a bottom wall extending laterally ofsaid wire with a stock discharging lower lip, and an adjustable frontwall assembly having wall structures including an upper portion and alower portion projecting forward of said upper portion with an upper liphaving a leading edge in close proximity to a portion of said wire andabove said lower lip to define therebetween a stock outlet opening,means for adjusting said front wall assembly comprising: a verticalsupport wall connected to said wall structures extending forward of saidupper portion and upwardly of said lower portion and said upper lip; apantographic link-age assembly defining a plane parallel to said supportwall, said linkage having a forward vertical link forward of saidsupport wall and directly above said leading edge, a rear vertical linkin close proximity to the rear of said support wall, an intermediatevertical link in close proximity to the front of said support wall, apair of vertically spaced parallel links transverse to said verticallinks and pivotally connected thereto at each intersection therewith,said intermediate and said rear vertical links having extensionsdownwardly of the bottom one of said transverse links, and a shaftthrough each said extension pivotally connecting the lower end of saidintermediate and rear links to said support wall at locations where thecentral axis of each said shaft defines a plane coincident with saidleading edge; and a lifting device connected to said rear link foradjusting the profile of said stock outlet by pivoting said front wallassembly about a substantially fixed lateral axis substantiallycoincident with said leading edge.

2. In a paper machine having a looped forming wire, a stock flowdistributing headbox comprising a bottom wall extending laterally ofsaid wire with a stock discharging lower lip, and an adjustable frontwall assembly having wall structures including an upper portion and alower portion projecting forward of said upper portion with an upper liphaving a leading edge in close proximity to a portion of said wire andabove said lower lip to define therebetween a stock outlet opening,means for adjusting said front wall assembly comprising: a verticalsupport wall connected to said Wall structures extending forward of saidupper portion and upwardly of said lower portion and said upper lip; apantographic linkage assembly defining a plane parallel to said supportwall, said linkage having a forward vertical link forward of saidsupport wall and directly above said leading edge, a rear vertical linkin close proximity to the rear of said support wall, an intermediatevertical link in close proximity to the front of said support wall, apair of vertically spaced parallel links transverse to said verticallinks and pivotally connected thereto at each intersection therewith,said intermediate and said rear vertical links having extensionsdownwardly of the bottom one of said transverse links, and a shaftthrough each said extension pivotally connecting the lower end of saidintermediate and rear links to said support wall at locations where thecentral axis of each said shaft defines a plane coincident with saidleading edge; a first lifting device connected to said forward link forsetting clearance of said edge over said wire; and a second liftingdevice connected to said rear link for adjusting the profile of saidstock outlet by pivoting said front wall assembly about a substantiallyfixed lateral axis substantially coincident with said leading edge.

3. In a paper machine having a looped forming wire, a stock flowdistributing headbox comprising a bottom wall extending laterally ofsaid wire with a stock discharging lower lip, and an adjustable frontwall assembly having wall structures including an upper portion and alower portion projecting forward of said upper portion with an upper liphaving a leading edge in close proximity to a portion of said wire andabove said lower lip to define therebetween a stock outlet opening,means for adjusting said front wall assembly comprising: a verticalsupport wall connected to said wall structures extending forward of saidupper portion and upwardly of said lower portion and said upper lip; apantographic linkage assembly defining a plane parallel to said supportwall, said linkage having a forward vertical link forward of saidsupport wall and directly above said leading edge, a rear vertical linkin close proximity to the rear of said support wall, an intermediatevertical link in close proximity to the front of said support wall, apair of vertically spaced parallel links transverse to said verticallinks and pivotally connected thereto at each intersection therewith,said inter-mediate and said rear vertical links having extensionsdownwardly of the bottom one of said transverse links, and a shaftthrough each said extension pivotally connecting the lower end of saidintermediate and rear links to said support wall at locations where thecentral axis of each said shaft defines a plane coincident with saidleading edge; a first lifting device connected to said forward link forsetting clearance of said edge over said wire; a second lifting deviceconnected to said rear link for adjusting the profile of said stockoutlet by pivoting said front wall assembly about a substantially fixedlateral axis substantially coincident with said leading edge; and athird lifting device pivotally connected to the top of said support walland operative to apply a lifting force to said support wall to apply andmaintain load upon said pivotal connections.

4. In a paper machine having a forming wire looped around a breast roll,a stock flow distributing headbox comprising a bottom wall extendinglaterally of said wire with a stock discharging lower lip in closeproximity to a portion of said wire on an upwardly turning portion .ofsaid breast roll below the top of said breast roll, and an adjustablefront wall assembly having wall structures including an upper portionand a lower portion projecting forward of said upper portion with anupper lip having a leading edge in close proximity to a portion of saidwire forward and above said lower lip to define therebetween a stockoutlet opening, means for adjusting said front wall assembly comprising:a vertical support wall connected to said wall structures extendingforward of said upper portion and upwardly of said lower portion andsaid upper lip; a pantographic linkage assembly defining a planeparallel to said support wall, said linkage having a forward verticallink forward of said support wall and directly above said leading edge,a rear vertical link in close proximity to the rear of said supportwall, an intermediate vertical link in close proximity to the front ofsaid support wall, a pair of vertically spaced parallel links transverseto said vertical links and pivotally connected thereto at eachintersection therewith, said intermediate and said read vertical linkshaving extensions downwardly of the bottom one of said transverse links,and a shaft through each said extension pivotally connecting the lowerend of said intermediate and rear links to said support wall atlocations where the central axis of each said shaft defines a planecoincident with said leading edge; and a second lifting device connectedto said rear link for adjusting the profile of said stock outlet bypivoting said front wall assembly about a substantially fixed lateralaxis substantially coincident with said leading edge.

5. In a paper machine having a looped forming wire looped around abreast roll, a stock flow distributing headbox comprising a bottom wallextending laterally of said wire with a stock discharging lower lip inclose proximity to a portion of said wire on an upwardly turning portionof said breast roll below the top of said breast roll, and an adjustablefront wall assembly having wall structures including an upper portionand a lower portion projecting forward of said upper portion with anupper lip having a leading edge in close proximity to a portion of saidwire forward and above said lower lip to define therebetween a stockoutlet opening, vmeans for adjusting said front wall assemblycomprising: a vertical support wall connected to said wall structuresextending forward of said upper portion and upwardly of said lowerportion and said upper lip; a pantographic linkage assembly defining aplane parallel to said support wall, said linkage having a forwardvertical link forward of said support wall and directly above saidleading edge, a rear vertical link in close proximity to the rear ofsaid support wall, an intermediate vertical link in close proximity tothe front of said support wall, a pair of vertically spaced parallellinks transverse to said vertical links and pivotally connected theretoat each intersection therewith, said intermediate and said rear verticallinks having extensions downwardly of the bottom one of said transverselinks, and a shaft through each said extension pivotally connecting thelower end of said intermediate and rear links to said support wall atlocations where the -cen tral axis of each said shaft defines a planecoincident with said leading edge; a first lifting device connected tosaid forward link for setting clearance of said edge over said wire; asecond lifting device connected to said rear link for adjusting theprofile of said stock outlet by pivoting said front wall assembly abouta substantially fixed lateral axis substantially coincident with saidleading edge; and a third lifting device pivotally connected to the topof said support wall and operative to apply a lifting force to saidsupport wall to apply and maintain load upon said pivot-a1 connections.

6. A stock flow distributing headbox having structures in fixedlocations, and an adjustable front Wall assembly having wall structuresincluding an upper portion and a lower portion projecting forward ofsaid upper portion with an upper lip having a leading edge to definetherebeneath a stock outlet opening, means for adjusting said front Wallassembly comprising: a vertical support wall connected to said Wallstructures extending forward of said upper portion and upwardly of saidlower portion and said upper lip; a pantographic linkage assemblyconnected to said fixed structure and said support wall and defining aplane parallel to said support wall, said linkage having a forwardportion directly above said leading edge and a portion rearward of saidforward portion connected to said support wall, a first lifting deviceconnected to said forward portion for setting the vertical position ofsaid edge relative to said fixed structure; a second lifting deviceconnected to said rearward portion for adjusting the profile of saidstock outlet by operating said pantographic linkage to pivot said frontwall assembly about a substantially fixed lateral axis substantiallycoincident with said leading edge.

7. A stock flow distributing headbox having structures in fixedlocations including a bottom wall extending laterally thereof with astock discharging lower lip, and an adjustable front wall assemblyhaving Wall structures including an upper portion and a lower portionprojecting forward of said upper portion with an upper lip having aleading edge above said lower lip to define therebetween a stock outletopening, means for adjusting said front wall assembly comprising: avertical support wall connected to said wall structures extendingforward of said upper portion and upwardly of said lower portion andsaid upper lip; a pantographic linkage assembly connected to said fixedstructures and said support wall defining a plane parallel to saidsupport wall, said linkage having a forward portion directly above saidleading edge, and a portion rearward of said forward portion pivotallyconnected to said support wall, a first lifting device connected to saidforward portion for setting clearance of said edge over said lower lip;a second lifting device connected to said rearward portion for adjustingthe profile of said stock outlet by operating said pantographic linkageto pivot said front wall assembly about a substantially fixed lateralaxis substantially coincident with said leading edge; and a thirdlifting device pivotally connected to the top of said support wall andoperative to apply a lifting force to said support wall to apply andmaintain load upon said pivotal connections.

References Cited UNITED STAT ES PATENTS 3,014,527 12/1961 Beachler 162-347 X FOREIGN PATENTS 697,321 9/1953 Great Britain.

DONALL H. SYLVESTER, Primary Examiner. A. C. HODGSON, AssistantExaminer.

1. IN A PAPER MACHINE HAVING A LOOPED FORMING A WIRE, A STOCK FLOWDISTRIBUTING HEADBOX COMPRISING A BOTTOM WALL EXTENDING LATERALLY OFSAID WIRE WITH A STOCK DISCHARGING LOWER LIP, AND AN ADJUSTABLE FRONTWALL ASSEMBLY HAVING WALL STRUCTURES INCLUDING AN UPPER PORTION AND ALOWER PORTION PROJECTING FORWARD OF SAID UPPER PORTION WITH AN UPPER LIPHAVING A LEADING EDGE IN CLOSE PROXIMITY TO A PORTION OF SAID WIRE ANDABOVE SAID LOWER LIP TO DEFINE THEREBETWEEN A STOCK OUTLET OPENING,MEANS FOR ADJUSTING SAID FRONT WALL ASSEMBLY COMPRISING: A VERTICALSUPPORT WALL CONNECTED TO SAID WALL STRUCTURES EXTENDING FORWARD OF SAIDUPPER PORTION AND UPWARDLY OF SAID LOWER PORTION AND SAID UPPER LIP; APANTOGRAPHIC LINKAGE ASSEMBLY DEFINING A PLANE PARALLEL TO SAID SUPPORTWALL, SAID LINKAGE HAVING A FORWARD VERTICAL LINK FORWARD OF SAIDSUPPORT WALL AND DIRECTLY ABOVE SAID LEADING EDGE, A REAR VERTICAL LINKIN CLOSE PROXIMITY TO THE REAR OF SAID SUPPORT WALL, AN INTERMEDIATEVERTICAL LINK IN CLOSE PROXIMITY TO THE FRONT OF SAID SUPPORT WALL, APAIR OF VERTICALLY SPACED PARALLEL LINKS TRANSVERSE TO SAID VERTICALLINKS AND PIVOTALLY CONNECTED THERETO AT EACH INTERSECTION THEREWITH,SAID INTERMEDIATE AND SAID REAR VERTICAL LINKS HAVING EXTENSIONSDOWNWARDLY OF THE BOTTOM ONE OF SAID TRANSVERSE LINKS, AND A SHAFTTHROUGH EACH SAID EXTENSION PIVOTALLY CONNECTING THE LOWER END OF SAIDINTERMEDIATE AND REAR LINKS TO SAID SUPPORT WALL AT LOCATIONS WHERE THECENTRAL AXIS OF EACH SAID SHAFT DEFINES A PLANE COINCIDENT WITH SAIDLEADING EDGE; AND A LIFTING DEVICE CONNECTED TO SAID REAR LINK FORADJUSTING THE PROFILE OF SAID STOCK OUTLET BY PIVOTING SAID FRONT WALLASSEMBLY ABOUT A SUBSTANTIALLY FIXED LATERAL AXIS SUBSTANTIALLYCOINCIDENT WITH SAID LEADING EDGE.